PSU Orientation

Zorba · 11 Jun 2010 at 15:41

I am a newbie to this site and just like to introduce myself: I have been a software engineer for many years, now retired for some 5 years. My last build was a dual P2 processor which I currently run. I thought it was time to build a new system and have gathered all the components apart from the memory.

Lian PC-P80B
Revelution85+ 1250w
Asus R3E
I7 980x
Megahalem,
Sapphire 5970 toxic 4GB
Crucial 256MB 300 SSD 6Gb/s, WD 1TB Caviar black, 6Gb/s (64MB Cache),WDRE4-GP 2TB SATA-II (64MB Cache).
Pioneer BDR205
Memory: Corsair 12GB - CMG6GX3A2000C8
NZXT Sentry 2 Touch Screen Fan Controller.

Since my new system is along the same lines as the OCuk’s supper gaming platform only higher specs, I thought you guys would be able to help: My problem is the orientation of the PSU, should I have the fan above or below. The P80 case has an extractor fan on top and therefore draws air out in that direction. If I have the fan on top, it will disrupt the airflow out of the top of the case while drawing air in from the rear top vent. The PSU shelf of the P80 has holes and if the PSU is fitted with the fan down although some intake is obscured it will take in the flow from the CPU cooler (Megahalem). Looking at the PSU from the rear in this orientation (fan down) the switch is below the socket, leading me to suspect that the correct orientation is fan up, i.e. power switch above the socket, any ideas? :confused:

C64 · 11 Jun 2010 at 16:04

Bottom fan facing down if theres a filter there under the psu spot if not fan facing upwards towards the board
Having said that I would have fan facing up if the case is going on carpet

Front fans intake
top fans exhaust
rear fan exhaust

Zorba · 11 Jun 2010 at 16:27

Thanks 64, The PSU rack is above the Mobo near the top case fan.

thingemajib · 11 Jun 2010 at 17:10

then the PSU fan should face down, because all the heat will rise from the components, the PSU fan will suck it in (this is normal, sucking in slightly warmer air wont harm a PSU), and blow it out of the back of the case.

on a different note, that PSU is a bit much. you should be looking in the region of 850w, 1000w tops. eg:

http://www.overclockers.co.uk/showproduct.php?prodid=CA-019-CS&groupid=701&catid=123&subcat=
http://www.overclockers.co.uk/showproduct.php?prodid=CA-012-CS&groupid=701&catid=123&subcat=

C64 · 11 Jun 2010 at 17:13

Sorry my bad I presumed this case allowed top or bottom mounted psu

I wouldn't get this case if it doesn't allow you to have psu at the bottom

Look for another case how much were you going to pay for this case there's far better cases out there

I am quite shocked this case only allows for top psu mounting

Zorba · 11 Jun 2010 at 17:20

The rack is on the top, I haven’t looked at the pos of moving the psu bay, but anything is possible.

Zorba · 11 Jun 2010 at 17:23

The Sapphire 5970 toxic 4MB uses a lot of power!
Sapphire suggests 850W for 1 and 1200W in XFire mode.

C64 · 11 Jun 2010 at 17:29

The pros are the psu gets less hot because it's not sucking in warm air rising from the cpu heatsink

Zorba · 11 Jun 2010 at 18:04

C64 said:
The pros are the psu gets less hot because it's not sucking in warm air rising from the cpu heatsink

My concern with that is it will draw the air away from the top fan (fighting each other).
If facing down, the support tray partially obstructs the fan intake of the psu!!!

C64 · 11 Jun 2010 at 19:04

Okay I just had a look at the case in more detail yes it's top mounted psu only seems like you only have one choice unless theres a nice gap between the psu and the very top of the case.

Zorba · 12 Jun 2010 at 14:39

Yes there is about 7cm above the PSU with the rear case vent above and the top fan in the middle of the case. I have put the PSU fan side down, it sits on the two side rails and the middle section of the shelf is sunken about 1mm which is also perforated with 2cm holes. I can also raise the PSU about 2mm more, which makes 3mm. The rear case fan is almost in direct line with the CPU and the two fans for the mega. I think the hot air will be split between the two. The PSU has a variable speed fan controller therefore I think it can handle it. When I can purchase the ram and put it all together, perhaps I should use one of the temperature probes of the motherboard to check the input air of the PSU. What do you think?